Issue No.01 - January (1970 vol.19)
Harry C. Andrews , ITT Electro-Physics Laboratories, Inc., Hyattsville, Md.; Department of Electrical Engineering, University of Southern California, Los Angeles, Calif. 90007.
A technique is presented to implement a class of orthogonal transformations on the order of pN log<inf>p</inf> N operations. The technique is due to Good  and implements a fast Fourier transform, fast Hadamard transform, and a variety of other orthogonal decompositions. It is shown how the Kronecker product can be mathematically defined and efficiently implemented using a matrix factorization method. A generalized spectral analysis is suggested, and a variety of examples are presented displaying various properties of the decompositions possible. Finally, an eigenvalue presentation is provided as a possible means of characterizing some of the transforms with similar parameters.
Harry C. Andrews, "A Generalized Technique for Spectral Analysis", IEEE Transactions on Computers, vol.19, no. 1, pp. 16-25, January 1970, doi:10.1109/TC.1970.5008895